The Gustavus author and his wife, Melanie, spend their winters traveling around the Antarctic coast as shipboard lecturers on National Geographic tour expeditions.

One of the dramatic spectacles they've been able to see in progress: the break-off of the 60-mile long Larsen Ice Shelf in 2002.

"There's growing evidence that (other) major ice shelves are beginning to destabilize," Heacox said Monday, noting that loss of the ice shelves can trigger further glacial losses. "It's like taking a cap off of a tube of toothpaste," he explained.

Heacox, a longtime freelance photographer and book author, is putting together a new glossy account for National Geographic Books titled "Restless Ice: The Arctic and Antarctic in an Age of Global Warming." The book is scheduled for publication in October 2007.

He will give a slide show presentation on his new subject matter in Juneau at 7 tonight at the University of Alaska Southeast. Heacox is the second of five speakers hosted by the Bread Loaf School of English's summer literature program at UAS.

Including Heacox, three of the Bread Loaf lecturers focus on land issues. Juneau ecologist Richard Carstensen lectured last Wednesday on Southeast Alaska's remaining large, ancient trees. On July 21, Fairbanks author Dan O'Neill will speak about his new book, "A Land Gone Lonesome," based on his canoe-based voyage and historical research on the Yukon River.

Other lecturers include Heather Lende, Haines author of "If you Lived Here, I'd Know Your Name," on July 18, and Ernestine Hayes, who is publishing a memoir this fall, entitled "Blond Indian: An Alaska Native Memoir," on July 26.

Heacox will deliver his lecture in Room 112 of the Egan Building. The final three speakers will give their lectures in the UAS library.

"I think we have a nice variety of voices," said Eileen Clark, who coordinates the Bread Loaf graduate school program for UAS.

Heacox will show photos of Alaska and Antarctica drawn from his travels in the regions over the last 13 years.

Though Antarctica holds 90 percent of the world's ice, Alaska is the spot most people are watching for the effects of climate change, Heacox added. Whether it's polar bears or coastal communities, the effects are much more striking here, Heacox said.

Heacox calls his book a "large, head-scratching project," one that mostly celebrates the beauty and scientific wonders of the icy regions, but also tackles the consequences of global warming.

"We'll talk about the psychology of denial a little bit, but we also need to be careful. I'm not so convinced (global warming) is the end of the world, but I'm also intrigued by people who have developed a world view where environmentalism is always 'Chicken Little,'" Heacox said.

 Elizabeth Bluemink can be reached at elizabeth.bluemink@juneauempire.com.